1. Field of the Invention
This invention relates generally to semiconductors and more particularly relates to an apparatus, system, and method for cleaning surfaces involved in semiconductor manufacturing.
2. Description of the Related Art
In semiconductor manufacturing, cleanliness is desired in order to improve the yield of acceptable semiconductor chips made during the manufacturing process. Previously, particles have been removed by exposing them to an acoustic wave in a liquid media is through cavitation. An active acoustic transducer can cause cavitation, and the collapse of cavitation bubbles create surface jet flows that dislodge particles.
Megasonic cleaners that utilize cavitation by generating acoustic waves with frequencies in the range of 0.5 to 3.0 MHz have been used for removing particles with diameters larger than 500 nanometers from surfaces. Particle removal efficiency increases as the frequency of acoustic waves increases. Particle removal efficiency also increases with acoustic power density. Typically, large acoustic transducers, for example 10 millimeters on an edge, have been used to create sufficient acoustic power densities. But since typical transducer materials have resonant frequencies inversely proportional to size, the frequency range of large transducers and the particle removal efficiency of megasonic cleaners have been limited. Thus, the ability of megasonic cleaners to safely remove particles smaller than 500 nanometers with high resonant frequencies has also been limited.
The referenced shortcomings are not intended to be exhaustive, but rather are among many that tend to impair the effectiveness of previously known techniques concerning particle removal from surfaces in semiconductor manufacturing processes; however, those mentioned here are sufficient to demonstrate that the methodologies appearing in the art have not been satisfactory and that a significant need exists for the techniques described and claimed in this disclosure.